In the manufacture of quilted comforters and of quilted multilayered fabric used for the outer coverings of mattresses, automated quilting machines that stitch patterns under the control of programmed computers or controllers are employed. The stitching of patterns onto such quilts is customarily carried out in one of two types of manufacturing processes.
In one type of process, the quilting is performed onto webs of multilayered fabric, usually with multineedle quilting machines, and arrays of patterns are sewn as the web is fed and shifted beneath a stationary array of needles. After the web is quilted, individual panels are cut from the web. Such a process is used in the manufacture of mattresses covers, particularly.
In another type of process, and the one to which the present invention most particularly relates, individual unquilted comforters and individual unquilted mattress covers are preformed into rectangular panels of several layers of fabric and sewn together, usually only around the edges. Such unquilted mattress cover panels and comforters, which are herein sometimes referred to as merely panels or comforter bags, are typically stretched onto rectangular racks or frames, usually made of wood or metal, which are fed into the quilting machines. The frames carrying the stretched panels are then caused to move in relation to a quilting head in accordance with a pattern control, which may be a mechanical template or programmed pattern controller or computer.
Movement of the panel relative to the quilting or sewing head is achieved by either x-y motion of the rack beneath a stationary sewing head, by x-y movement of the sewing head over a fixed rack or frame, or by reciprocation of the rack in the machine under a quilting head in a longitudinal direction while the head reciprocates across the machine frame in a transverse direction, stitching a pattern on the panel as the head and frame are being moved. The motion of the rack beneath the quilting or sewing head and the motion of the head across the machine provide planar x-y motions that are carried out under the control of a program control device so that a particular pattern is stitched onto the panel. Full panel-size patterns requiring 360.degree. motion of the head relative to the frame can be stitched in this way.
Devices that employ such frames or racks to support and stretch the panels as they are fed into or through a quilting machine suffer the disadvantage of requiring labor intensive handling of the panels, both before and after quilting, to mount the unquilted panels on the frames for feeding into the machines and to remove the finished quilts from the frames after the quilting process is complete. With quilting machines being made increasingly faster, the loading and unloading of such quilts onto and off of such frames or racks becomes a major time consuming factor affecting the productivity of the entire quilting process, either by slowing the rate at which the panels can be quilted by the machines to less than the capacity of the machine or by requiring additional operators to handle the workpieces and finished products to keep up with the speed of the machine.
Attempts have been made to provide quilting machines that eliminate the separate rack or frame by providing the machine with built-in panel-supporting and stretching structure into which the panels can be directly loaded onto the machine and fed into a quilting station. The difficulty in providing such permanent supporting structure, which must include structure for gripping all four sides of the panels to stretch the panels therebetween, is in efficiently and effectively mounting and removing of the panels to and from the structure on the machine. The mounting and removing of the panels to and from such machines must be carried out in real time on the machine, which can slow down the machine and interfere with the machine throughput by the amount of time it takes to load and unload the panels.
Accordingly, a long standing need has existed in the single panel quilting art for an quilting apparatus and process that does not require separate panel supporting racks or frames and that can easily and reliably load and unload panels onto mounting and stretching structure on the quilting machine without material interruption or delay of the quilting operation of the machine.